not-os

kernel

$ nix-build -A kernel
/nix/store/9mgs63lqf5fh62xxy3rkqldl22d27zd6-linux-5.4.119

The kernel derivation results in an actual kernel, a bzImage file, but also in a set of kernel modules.

The modules are packaged in the shrunk derivation, which itself is used to create the initrd.